13MARAMA

Strange that marama has not been introduced into cultivation. Above ground, this plant produces seeds that rival peanut and soybean in composition and nutritive value. Below, it produces a high-protein tuber much bigger and more nutritious than any potato, yam, or even sugar beet. And the plant also yields top-quality vegetable oil. In addition, it thrives in poor-quality soil and under the harshest of climates. Indeed, in its native habitat droughts often last years on end, a feature ruinous to mainstream crops and most living creatures but not to marama.

Moreover, the life-giving propensities of this resilient species are by no means restricted to food. The plant probably survives the seemingly interminable droughts by drawing on water stored in its tuber, which in dry years shrinks dramatically. Some of those tubers hold an immense amount of water. One dug up in Botswana weighed 277 kg, perhaps 250 kg of which would have been water. In arid and semiarid regions these “living cisterns” become important emergency sources of water for both humans and animals.

Despite these surprising qualities, though, little is known about the plant and almost nothing is understood about its cultivation. Among Africa’s many native foods, this remains one of the most neglected. Yet, the record clearly shows that a dedicated research and development effort might well lift this wild species out of obscurity and perhaps project it far enough to contribute importantly to the food supply in some of the most challenging of all agricultural locations.

Marama is endemic to southern Africa. Native to the Kalahari and neighboring sandy lands, it has a long history as a resource. Indeed, humankind is believed to have originated in this general area; marama may have been in our diet as long as any food in existence. Even today it is an important dietary component for some in the region. People in remote settlements and among nomadic groups rely on it as did our earliest ancestors. It is, for instance, a popular delicacy of the Herero, Tswana, and other Bantu-speaking peoples and is a key part of the diet of some Khoisan peoples (!Kung and Khoi-khoi). For some !Kung only mongongo nut surpasses it in importance as a life-sustaining foodstuff.

For all that, the plant has never been regularly cultivated. This is what is so strange. Marama is a rich source of protein and energy, and nourishes

Marama is a wild plant of the southern African deserts. A source of concentrated protein and energy, it nourishes people in regions where rainfall is so slight and erratic that in some years almost no moisture falls whatever. The plant withstands blistering temperatures with ease. It thrives in poor-quality soil. But it remains undomesticated and before anyone can truly capitalize on its amazing qualities a wealth of horticultural development is needed. (Lorna K. Marshall)

people in desert regions where rainfall is so slight and erratic that in some years there is almost no precipitation whatever. The plant withstands blistering summer temperatures apparently with ease. In addition, it survives low winter temperatures, especially the freezing nights of the Kalahari. And yet it is not being raised under the kind of controlled conditions that could bring out its best.

This neglect is not due to scarcity. Within the Kalahari region this is not a rare plant. In some areas of Botswana and Namibia, marama occurs in stands several kilometers across. It is found to a lesser extent in South Africa (northern Cape Province and Gauteng). The typical habitat is an undulating grassveld (savanna), with marama sprouting among the native grass and acacia-thorn scrub on sandy vlies.

It is not due to an unpleasant taste. After roasting the seeds take on a nutty flavor that has been compared with roasted cashew nuts. Europeans in southern Africa have ground the roasted seeds and used them as a culinary substitute for almonds. Africans often boil them with cornmeal or grind or pound them into a powder that is boiled in water to produce either a cocoa-like beverage or a porridge. In taste, then, marama ranks with the best.

Nor is it due to the impossibility of producing the plant in an organized manner. Although no concerted effort at domestication has been undertaken,

it was reported in the early 1960s that, for 20 years, farmers near Barberspan (Western Gauteng) had encouraged the plant by sowing its seeds in spring (October) directly into sand without any preliminary plowing. Following the mention of marama in an earlier book from this office,1 trials were reported in several parts of the United States in projects located in Texas, Florida, and California, and the plant grew satisfactorily.

PROSPECTS

Despite the fact marama is still a wild plant with vast uncertainties to answer before it can cultivated on any scale, marama seems to have notable prospects solely on the basis of its nutritional composition. By that measure it ranks with soybean and peanut, the two most commercially important legumes, each grown on millions of hectares worldwide. Add to that its rugged constitution and ability to grow where other food crops cannot and the conclusion would seem that this is definitely a plant with prospects.

Within Africa

At first sight there doesn’t seem to be much doubt about this plant’s potential within its home range. On its web page, one South African university refers to marama as “a versatile legume and potentially high-protein, sustainable food crop for Africa.” It also calls it the “magic marama bean, the green gold of Africa.” But everyone should realize that there’s many a challenge to be overcome before its promise is realized even in the lowest degree.

Humid Areas Although this is an extremely interesting species for any plant lover to work with, its prospects as a useful crop in the humid tropics do not seem high. Better-known tubers and leguminous seed crops— cassava, yam, peanut, and bambara bean, for example—are immediately available for this climatic zone.

Dry Areas Given its extreme drought tolerance, the marama offers the possibility of a new crop highly suited to the compelling needs of semiarid lands. In principle at least it should be tested in projects aimed at alleviating rural poverty and malnutrition in the drought-prone sandy zone of southern Africa.

Upland Areas The prospects here are unknown and uncertain. Any but the most preliminary tests are probably best left until more is learned about the plant and its wider prospects.

Beyond Africa

Marama will certainly grow beyond Africa. As noted, researchers in places such as the United States, Australia, and elsewhere have trialed it. But in such places it is likely to remain a marketplace curiosity, given the high performance of peanuts, soybeans, and similar crops.

USES

Like many of the species in this report, this plant has a surprising number of practical uses.

Seeds When taken straight from the freshly picked pod the seeds are soft and white and virtually inedible, being nearly tasteless and having an unpleasant, oily texture. Later, they harden, turn brown and become more appealing. They can then be eaten raw but most are first roasted, after which they have a delicious nutty flavor that has been compared to roasted cashew nuts. In this form they are very much liked by groups throughout the region. They are also often boiled with cornmeal, or pounded, mixed with hot water, and made into a delicious soup.

Oil Conventional presses or solvent extraction methods produce a clear and golden-yellow oil from the seeds. It has a pleasant nutty odor and agreeable taste, is similar to almond oil in consistency and appearance, and appears suitable for use in cooking and foods. It is a polyunsaturated oil and seems a good source of linoleic acid, one of the nutritionally essential fatty acids. The meal remaining after oil extraction has a remarkable 52-percent protein content, which could give it a place in local foods or feeds.

Tubers The succulent red-brown tuber, shaped like a giant top waiting to be spun, can attain enormous weights, as attested by the one in Botswana that achieved almost 300 kg. Normally, inhabitants of the Kalahari dig up young tubers when they weigh about 1 kg. Baked, boiled, or roasted whole, these have a sweet, pleasant flavor and make a good vegetable dish.

Feeds This plant is eaten by both people and animals. Livestock savor the beans, which are said to be especially good for fattening pigs.

Other Uses Wildlife relies on the plants for food and water. Because the gemsbok (a large antelope) eat the seeds and tubers with great relish, the plant is often called gemsbok bean.

NUTRITION

The marama bean analyses made so far have reported record protein contents of 30, 34, and 39 percent. Thus, the marama seed has a protein

content that rivals that of soybean (37-39 percent). Like most legume proteins, marama-protein is rich in lysine (5 percent) and deficient in methionine (0.7 percent).

An extensive study made at Colorado College showed marama essential amino acid content is also comparable to soybean. Indeed, its protein proved superior in nutritional quality to most common legume crops, such as garden bean and pea. It had more albumin and less globulin than soybean protein, making it more digestible and more readily available to the body.2

The seeds are a great source of food energy as well. Oil content is reported as 36-43 percent of the dry seed by weight. Thus, its oil content is about twice that of soybean, and approaches that of peanut.

The seeds are not only a good source of protein and energy but of nutritionally important minerals and vitamins, including potassium, phosphorus, thiamin, riboflavin, and nicotinic acid as well. They have less than half the fiber of peanuts, a feature both good and bad.

The edible underground portion of the plant is also nutritious, with tubers containing about 9 percent protein dry-weight.

HORTICULTURE

The plants are propagated by seed, which germinate readily in moist soil if scarified; soaking, however, rots them. Sprout-propagation has been done experimentally. Leaves often die back under drought or cold, but the storage root allows them to regrow quickly. This adaptation builds up root storage

and reduces moisture losses due to transpiration. Beyond this, little has been reported on the means of managing a sprawling marama crop. It may turn out that some growers focus on seed production, and others on tubers.

HARVESTING AND HANDLING

Currently, seeds are picked and tubers dug by hand. Raw seeds store well and remain edible for years. Roasting them in their shells makes them easy to open. Before eating, the beans must be carefully peeled.

LIMITATIONS

This plant is so neglected that the very lack of knowledge is perhaps its major limitation. Before wide-scale cultivation could be undertaken with any degree of confidence, information is needed on its adaptability to cultivation and on all aspects of its agronomy. Other limitations include the following.

While the plant has a wide distribution, it occurs patchily in very localized stands, perhaps indicating special soil requirements. Sand seems to be the common denominator. And that makes sense with a crop whose tuber needs to swell and not be restricted by soil pressure.

Even under good conditions, seeds may appear only after 2-4 years, and it may take as long for tubers to reach marketable size, after which they can become fibrous and astringent. Some tubers also have a tough, leathery skin.

Some writers have reported that the seeds can taste slightly bitter and that the hard shell surrounding them is a hindrance to their use as oilseeds. According to one correspondent, an excess of roasted seeds has a strong purging effect, but this is not widely reported.

Like soybean, the marama contains a potent trypsin inhibitor activity. This occurs in the protein fractions (both water-soluble and saline-soluble) and is destroyed by the heat of normal cooking.3

NEXT STEPS

Of course the marama is still a long way from being a cultivated plant. Even in their native region the bean is not a firmly established article of commerce. This means that there are many things to be done. In fact, this plant needs to be attacked on several knowledge fronts.

Protection Wild stands offer a wealth of different germplasm, but are being exterminated in many areas. For one thing, the land is being plowed and planted with maize or sunflower. For another, the seeds are being relentlessly harvested for village use and for sale. A third threat comes from the cattle ranching that now extends deep into the Kalahari region, as livestock eagerly devour the plant’s leaves and runners.

Documented and approved germplasm collections should be made immediately and desirable strains selected. Initially, strains should be selected on the basis of productivity; to date, no single yield, measured or estimated, is reported. Vigorous strains producing large numbers of pods, bigger seeds, or more seed per pod could change the whole picture of the plant’s future. Furthermore, strains that yield especially well under adverse conditions should be sought in the harshest sites.

In a related vein, the wisdom of the Kalahari peoples needs to be compiled in easily accessible form. As traditions are abandoned in favor of agricultural, pastoral, or industrial activities, their intimate knowledge of the bean and its use is being lost. Some of this has been done already, and those records need to be extracted from obscure and inaccessible reports and made accessible to plant scientists and others—especially these peoplesthemselves—who can help foster the marama’s progress.

Use of the Wild Resource This plant seems an ideal tool for battling the scourge of desertification. This is a spreading species that sprawls across the land, protecting the soil from wind, rain, and sun. For the support of traditional cultures and ways of life, marama could be an outstanding tool. If production could be increased in the Kalahari, many would benefit.

The residual meal left after oil extraction contains about 50 percent protein and should be valuable for food and feed uses, but nutritional and analytical trials are necessary to undercover any undesirable factors.

Horticultural Development Marama bean is not yet ready for large-scale cultivation but agronomic research is nonetheless badly needed. Among features deserving investigation are the plant’s requirements for altitude, temperature, moisture, soil type, fertilization, and latitude. Processes for enhancing growth also require documentation.

In addition, trials are needed for learning how to manage the plant as a crop. Cultural practices such as germination, spacing, planting, weeding, and pest and disease control all need study and evaluation.

Genetic improvement needs particular attention because today the plants produce too little seed for the fraction of the field they occupy.

Physiological Studies Because of this plant’s special importance for semiarid climates, botanists could provide useful information by detailing the mechanisms that allow it to survive extreme heat and desiccation. Temperatures sometimes reach 50°C in its native habitat and surface water is available usually for only 8 weeks a year.

Below ground, marama produces a tuber much bigger even than sugar beet and much more nutritious even than potato or yam. Compared with those and other root crops it is high in protein, containing about 9 percent on a dry-weight basis. (A.S. Wehmeyer)

Tuber Development The tubers warrant particular attention: composition, growth rate, occurrence of nonastringent types, and production potential in small plots should all be investigated.

Harvesting In the long term the greatest barrier to development of this plant may prove to be the mechanical one of how to gather the crop, both seed and tuber, from this sprawling, awkward-to-handle plant.

Description

The plant is not a climber; it grows prostrate, sending viney stems creeping out over the soil surface in several directions. These runners are up to 6 m long and form a dense, geometrical pattern of overlapping whorls of stems, hugging the ground, presumably to avoid the drying winds. The vines carry double-lobed leaves that are soft and red-brown when young, turning leathery and gray-green with age. Golden-yellow, insect-pollinated blossoms develop in midsummer (December/January in southern Africa) and the fruits ripen in late autumn (April).

Each fruit comprises a large, flat, woody pod enclosing one to six large beans. The pod starts out soft and reddish-brown, then turns light green and, when ripe, becomes chestnut-brown and woody. Each bean has a hard inedible outer shell and an edible two-lobed seed inside. Though hard, the woody shell is thin, brittle, and easily cracked. The normally spherical seeds are roughly the diameter of a thumbnail and weight about 2-3 g. Their inner flesh is firm, cream colored, oily, and almost without fiber.

During cooler months, the stems may die back but the underground tuber remains viable and, with returning warmth, shoots forth more stems. After a few years the tuber can weigh more than 10 kg. It can contain 90 percent water by weight. Tubers more than two years old become fibrous and/or astringent. In deep, loose, sandy soils, the plant is reported to form “craters,” sometimes over a meter across. These hollows in the landscape are often ringed with stones that appear to have been forced to the surface by the giant tuber swelling beneath.

The plant is a legume but it belongs to subfamily Caesalpinioideae and, like many of them, it fails to nodulate and fix nitrogen.

Distribution

Within Africa Occurs in the northern part of Namibia, Botswana, as well as the western and northwestern Transvaal and the northern Cape in south Africa.

Beyond Africa Reported in California, Texas, and Florida in the USA, Queensland in Australia, and Israel, and some botanic gardens. It has curiously become a favorite of some bonsai enthusiasts, so probably now has a broader, yet still small-scale distribution.

Horticultural Varieties

None reported.

Environmental Requirements

The marama survives in regions where few conventional crops survive, yet it appears adapted to a wide range of climatic conditions. Obviously, the plant’s environmental requirements are at present far from certain but the following seems a reasonable summary.

Rainfall Mainly, marama grows where rain is so slight and erratic that in some years almost no moisture falls at all. In some locations, even in the best of times, the rains last for only two months a year. The sparse precipitation arrives during short-lived torrential thunderstorms in spring and fall. The rest of the year remains almost rainless. Usually, however, there is subsoil moisture that the deep roots tap into. Indeed, in fine-grained sandy soils, water may remain in the root zone for months after rain. Marama also exists in well-watered locations receiving up to 800 mm annual rainfall.

Altitude The plant is found in a region lacking in mountains, but altitude seems hardly likely to be a limitation by itself.

Low Temperature In winter, when the plant is dormant, temperatures plunge very low (by African standards). Winter nights can be freezing and the days frosty.

High Temperature Very high summer temperatures to 47 °C in the shade and sometimes over 50° have been reported.

Soil Marama beans prefer neutral to acid soil. It is particularly prominent on the brick-red sand of the inland Namib Desert. Grows on deep sand but also where there are outcrops of dolomite; also has been grown on neutral shaly soils.

Related Species

Two related species may also be worth agronomic attention.

Tylosema fassoglense Grows from the Transvaal north through Central and East Africa to Sudan. This sprawling vine also yields edible seeds plus excellent livestock forage and a tuber with a wide variety of traditional medicinal uses. Like marama, the seeds are very high in protein (> 40 percent) and fats (> 30 percent), and widely appreciated.

Bauhinia petersiana A small shrub that grows together with the marama bean in open grasslands (as well as in sandy bushveld and woodlands) in Transvaal, Namibia, and Botswana, as well as in Angola and Zambia. The seeds can be eaten green, but ripe seeds are usually roasted, peeled, and pounded into a pleasant-tasting, coarse meal. The plant has been cultivated as an ornamental in South Africa and, given research, might also become a useful food crop for arid zones.

This report is the second in a series of three evaluating underexploited African plant resources that could help broaden and secure Africa's food supply. The volume describes the characteristics of 18 little-known indigenous African vegetables (including tubers and legumes) that have potential as food- and cash-crops but are typically overlooked by scientists and policymakers and in the world at large. The book assesses the potential of each vegetable to help overcome malnutrition, boost food security, foster rural development, and create sustainable landcare in Africa. Each species is described in a separate chapter, based on information gathered from and verified by a pool of experts throughout the world. Volume I describes African grains and Volume III African fruits.

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